Block for internal-combustion engines



Um. 3@, W51 F. J. STUCKERT 2,5733% BLOCK FOR INTERNAL-COMBUSTION ENGINESFiled Nov. 6, 1947 3 Sheets-Sheet l ct. w, 191

Filed Nov. 6, 1947 F. J. STUCKERT 2,573,116

. BLOCK FOR INTERNAL-COMBUSTION ENGI NE S s Sheets-Sheet 2 :5Sheet-She'et 3 Filed Nov. 6, 1947 Patentecl Oct. 30, 1951 2,573,116BLOCK FOR INTERNAL-COMBUSTION ENG INES

Felix J. Stuckert, Wauwatosa, Wis., assignor to Briggs & StrattonCorporation, Milwaukee, Wis., a corporation of Delaware ApplicationNovember 6, 1947, Serial No. 784,408

1 Claim.

This invention relates to internal combustion engines and has moreparticular reference to engine blocks of die cast construction.

Because of the advantage of lightweight construction, the manufacture ofinternal combustion engines using aluminum die castings for the block isbecoming more and more popular. Although aluminum die castings aredesirably light in weight, the metal is relatively soft and incapable ofwithstanding the wear incidental to the operation of such elements ofthe engine as valves and pistons, and it is customary to embed inserts,usually of cast iron, into the die cast blocks to slidably receive theseparts and to seat the valves of the engine.

At present these inserts are separately .embedded in the block at thetime of die casting the same; it being understood, of course, that theinserts are held in a predetermined position relative to one anotherduring the die casting operation.

While the inserts thus commonly employed have the ability to withstandconsiderable wear and afford excellent bearing and valve seatingsurfaces, engine blocks having such inserts have so far devised for thepractical application been found unsatisfactory by reason of the factthat the inserts have a different coefficient of expansion than thealuminum or other die cast metal from which the block is made; and thisdifferential in expansion made it impossible to maintain a predetermineddimensional relation-- ship between the inserts over the entire range ofoperating temperatures of the engine. In many instances the differentialof expansion between the inserts and. the die cast metal resulted inloosening of the inserts to a degree such as to seriously impair theoperation of the engine.

With these objections in mind it is an object of the present inventionto provide a die cast block for internal combustion engines having in.

serts of unitary design embedded in the die cast bustion engines with acombination valve and piston insert of unitary construction embedded inthe die cast metal.

With the above and other objects in view, which will appear as thedescription proceeds, this in-' vention resides in the novelconstruction, combination and arrangement of parts substantially ashereinafter described and more particularly defined by the appendedclaim, it being under-.

stood that such changes in the precise embodiment of the hereindisclosed invention may be made as come Within the scope of the claim.

The accompanying drawings illustrate two com plete examples of thephysical embodiment of the invention constructed according to the bestmodes of the principles thereof, and in which:

Figure 1 is a side elevational view of a small single cylinder internalcombustion engine of die cast construction with portions of the blockbroken away to show the application of this invention thereto;

Figure 2 is a plan view of the block per se illustrating the unitaryinsert of this invention embedded therein;

Figure 3 is a fragmentary sectional view through both valve seats takenalong the plane of the line 33 of Figure 2;

Figure 4 is a fragmentary sectional view through the intake valve seattaken along the plane of the line 4-4 of Figure 2;

Figure 5 is a fragmentary sectional view through the exhaust valve seattaken along the plane of the line 5-5 of Figure 2;

Figure 6 is a plan view of a block similar to Figure 2 but illustratinga slightly modified insert in place in the block;

Figure 7 is a sectional view similar to Figure 5 taken through Figure 6along the plane of the line '|.--'l; and

Figure 8 is a detail sectional view through a portion of the block takenalongthe plane of the 1ines 88 of Figure 6.

Referring now more particularly to the accompanying drawings whereinlike numerals indicate like parts, the numeral 5 represents a singlecylinder internal combustion engine of the air-cooled type having anupright block 6 of die cast aluminum, and a head 1 secured substantiallflatwise upon the fiat top surface 8 of the block. While the head 1forms no part of this invention, it and the base for the block may alsobe aluminum die castings in keeping with the lightweight construction ofthe engine.

The upper portion of the block at one side thereof is provided with afinned cylinder 9 to receive a piston (not shown) and as is usual the(not shown) at the side of the block opposite the cylinder 9, includingtappets adapted to be housed within a chamber I0 alongside the cylinderand closed by the usual detachable cover.

In accordance with this invention a single unitary insert I2 is embeddedin the die cast metal of the block in the upper portions thereof, andthis insert comprises a relatively fiat plate I 3 the top surface .ofwhich is flush with the surface 8 at the top of the block, a cylinderliner or sleeve l4 integrally joined with the plate and depending fromits underside to define the bore of the cylinder, and valve mounts l5and 6 for the intake and exhaust valves respectively. The valve mountsare likewise formed integrally with the-plate i3 and extend downwardlytherefrom alongside the cylinder liner.

Valve seats I! are machined directly in the top surface of the plate andgas passages are provided in each of the valve mounts for the flow offuel into the head and for the exhaust of burned gases from the head. Inboth valves the passages include an upright branch [9 beneath the valveseat and a lateral branch 20 extending at right angles from the lowerportion of the upper branch. The lower branches 2c are substantiallyhorizontal and open to the .side of the block opposite the cylinder toprovide for the introduction of fuel into the head and for the exhaustof burned fuel from the head as stated previously.

Ihe stems of the engine valves are received in vertical bores .22aligning with the valve seats H, and these bores are machined insubstantially cylindrical guide tubes 23 formed integral with the valvemounts and spaced a distance,

beneath the valve seats.

The insert 12 is preferably made of cast iron of a well known specialtype, as shown in Figures 1 to 5 inclusive, but the unitary aspect ofthe insert may also be attained by the construction illustrated inFigures 6 to 8 inclusive. In this latter instance the liner i4 isprovided by a sleeve having its upper end fixed in a suitable aperture25 in a steel plate l3 embedded in the top of the block to have its topsurface flush with the top surface 8 of the block as previouslydescribed.

To insure rigidity of the joint between the sleeve M and the plate 53the upper end of the sleeve may be turned down as indicated in Figure 7for an axial distance corresponding to the thickness of the plate l3 andso as to provide a shoulder 26 on the sleeve which abuts against theunderside of the plate. Although the reduced upper end portion ofthe-sleeve 14' may be pressed into the aperture 25 of the plate, maximumrigidity is achieved by brazing or welding the sleeve to the plate atthe joint 21 therebetween.

In this embodiment of the invention, the valve seats ll are machined inthe upper open ends of elbow-like inserts 28 carried by the plate at itsunderside as seen in Figure '7. The inserts 28 have their upright branchpressed into a suitable aperture 29 in the plate [3 and are likewisewelded or brazed thereto at the joint 30 so as to assure absoluterigidity between the insert and the plate. The horizontal branch of theinsert 28 leading from the bottom of the upright branch opens to theside of the block as shown in Figure 7, and if desired, a guide .tube 3!of special steel alloy may be brazed or welded in an aperture in thebottom of the insert in line with the seat thereof.

7 In each of the embodiments shown the inserts are of ferrous metal, 1.e. either steel or a special cast iron, and the unitary nature of theinserts assures against the difierential of expansion between the diecast metal and the inserts disrupting the dimensional relationshipbetween the components of the insert and particularly between the valveseats and guides.

Referring again to the Figure 1 to 5 embodiment of the invention, itwill be seen that the plate 13 forms but a small part of the top surfaceof the block, while the plate l3 of the Figure 6 embodiment providessubstantially the entire top surface of the block with the exception ofa relatively narrow annular rim at the extreme periphery of the block.In both instances,

however, the plate is formed to have portions of the die cast metalextend thereover.

In the-preferred embodiment the top surface of the plate l3is steppedalong its marginal edge as at 32 with the bottom of the step spacedbeneath the surface 8 o f the block so as to enable the die cast metalto flow over the step during casting and thus anchor the plate firmly'inplace on the block. This condition is best illustrated in Figure 3. Inthe Figure 6 embodiment, relatively small areas of the plate at theperiphery thereof'may be downwardly offset as indicated at 3 in Figure 8so as to allow the die cast metal to overlie the offset portion for thepurpose of securely anchoring the plate in place on the block.

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent to those skilled in the art thatthe unitary construction of the inserts of this invention assuresrigidity between its component parts to the end that the dimensionalrelationship between said components will be maintained throughout theentire range of operating temperatures of the engine.

What I claim as my invention is:

In a single cylinder internal combustion engine: a die cast block havinga relatively upright cylin der which opens to the top of the block: asubstantially rigid ferrous metal unit cast within the block, said unitincluding a plate-like member having a flat upper surface formingsubstantially the entire top surface of the block, a cylinder linerjoined to the plate-like member and extending downwardly therefrom intothe block to define the inner wall of the cylinder bore, valve seats onthe upper exposed surface of the plate-like member alongside thecylinder liner, valve guides joined to said plate-like member andextending downwardly therefrom in alignment with said valve seats, andmarginal edge portions on the periphery of said plate-like member spacedinwardly from the sides of the block and offset below said top surfaceof the plate-like member and covered by the die cast metal of the blockto securely anchor the ferrous metal unit in place in the block; and ahead detachably secured to the block at the top thereof and having afiat undersurface seating flatwise upon said flat top surface of theplate-like member.

FELIX J. STUCKERT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,220,335 Heinze, Jr Mar. 2'7,1917 2,085,810 Ljungstrom July 6, 1937 2,227,933 Hersey Jan. 7, 19412,280,660 Newcomb Apr. 21, 1942

